1. Field of the Invention
The present invention relates to a method for preparing phthalocyanine analogous which are useful as a dye, a pigment, a photoelectric functional material and a recording/memory material, particularly a recording material for writable (recordable) compact discs, and it also relates to a phthalocyannne compound.
2. Description of the Related Art
Techniques by which a phthalocyanine is applied to an optical recording medium are described in U.S. Pat. No. 4,298,975, EP 353,394 and U.S. Pat. No. 4,769,307. However, the phthalocyanines disclosed in these patents are insufficient in points of sensitivity and refractive index as phthalocyanines for optical recording media.
Particularly, in the writable (recordable) compact discs (CD-WO), laser beams in the vicinity of 780 nm are utilized for writing and reading of records, and therefore it is important to control the absorptivity coefficient, the refractive index and the reflectance of a recording material at about 780 nm. Thus, it has been desired to develop phthalocyanines suitable for recording materials for CD-WO which have a good structure stability, a high refractive index for beams at about 780 nm, excellent resolution properties and a high sensitivity.